Department of Therapeutic Radiology, College of Medicine, Seoul National University, Seoul, Korea.

ABSTRACT

Treatment of cerebellar medulloblastoma has been much improved with modern surgical technique for gross total tumor removal and adequate radiation therapy for the whole craniospinal axis. Questions have been arosen about the optimal radiation dose for the preventive treatment of whole cranium and whole spinal axis. Recently, many authors have reported their treatment results as comparable to older data, using lower than conventional dose of 3,600cGy-4,000cGy. For 50 patients treated between 1981 and 1950 at the Department of Radiation Therapy of SNUH, retrospective analysis was done for the treatment result, especially the neuraxis control, by radiation dose for the presymptomatic area of the disease. Analysis only by total spinal dose did not give any significant difference. But further analysis by following patient group: 3,600cGy/150cGy (n=S), 3,000cGy/150cGy (n=10), 2,400 cGy/150cGy (n=17) and 2,400cGy/100-120cGy (n=11) showed significant improvement of neuraxis control by decreasing order (p=0.003). There was no significant difference in overall survival between the groups. For the 19 patients who had been confirmed initially as having no neuraxis disease, TDF 30 was the cur-off value that could prevent neuraxis failure (p=0.004). We couldn't define any TDF value that give reasonable control for the patient group with positive CSF study at initial diagnosis.